1. Field of the Invention
The invention relates to a magnetic head driving piezoelectric ceramic actuator. Specifically, the invention relates to a piezoelectric ceramic actuator for finely adjusting the position of a magnetic head of a magnetic disk device.
2. Description of the Related Art
In the related art, in a magnetic disk device, a voice coil motor is used as an actuator for moving a magnetic head to a desired position on a disk. However, when the magnetic head is positioned by using the voice coil motor, it is difficult to sufficiently increase accuracy of positioning the magnetic head. Thus, there is a proposal of providing a fine-motion actuator between the magnetic head and a coarse-motion actuator such as a voice coil motor, for finely adjusting the position of a magnetic head. In addition, there is a proposal of using a piezoelectric ceramic actuator as a fine-motion actuator. This is because use of the piezoelectric ceramic actuator positions a magnetic head with high accuracy.
Incidentally, a piezoelectric ceramic actuator has a piezoelectric ceramic substrate made from a piezoelectric ceramic. The piezoelectric ceramic substrate is brittle and its mechanical strength is low. In addition, when the piezoelectric ceramic actuator is driven, the piezoelectric ceramic substrate expands and contracts. Thus, when the piezoelectric ceramic actuator is driven, fine dust may be generated from the piezoelectric ceramic substrate. Then, if the fine dust generated from the piezoelectric ceramic substrate attaches a magnetic head or a disk, or contaminates the inside of a magnetic disk device, reliability of reading or writing information is decreased.
In view of such a problem unique to the magnetic head driving piezoelectric ceramic actuator, for example, Japanese Unexamined Patent Application Publication No. 2002-163870 suggests coating a piezoelectric ceramic actuator for finely adjusting the position of a magnetic head, with a resin.
FIG. 5 is a perspective view of a magnetic head supporting mechanism disclosed in Japanese Unexamined Patent Application Publication No. 2002-163870. As shown in FIG. 5, a magnetic head supporting mechanism 100 includes: a suspension 102 having a slider 101 fixed at its end; and a suspension supporting mechanism 103. The suspension supporting mechanism 103 and the suspension 102 are connected to each other by a piezoelectric ceramic actuator 106 via adhesive layers 104 and 105. The surface of the piezoelectric ceramic actuator 106 is coated with a resin coating layer 107. Thus, fine dust is effectively prevented from being generated from the piezoelectric ceramic actuator 106.
However, in the magnetic head supporting mechanism 100, both edge portions of the bottom surface of the actuator 106 are merely connected to the suspension 102 and the suspension supporting mechanism 103 by the adhesive layers 104 and 105. Thus, the mounting strength of the actuator 106 is low.